The laboratory continues to work on newly identified strains of mycoplasma originated from AIDS patients. One of the isolates: Mycoplasma penetrans, is a new species of mycoplasma isolated from the urogenital tract of patients with AIDS. Genetic analysis of the DNA of this agent by liquid hybridization procedure has shown that this agent is a new species. This organism has properties of adherence, hemadsorption, cytadsorption and invades many different types of mammalian cells. Thus, it was so named: M. penetrans. Specific genetic clones and antibodies against this agent were prepared and were used to probe infected tissues. Attempts have been made to develop molecular and serological assays for the agent and specific immunoresponse to this agent. These assays were used to assess the significance of infectivity and pathogenicity of this agent in human.